In a Nov. 4 letter to the Federal Energy Regulatory Commission, the independent system operator that runs the New England grid — known as ISO-New England — has requested permission to cut Killingly from future power considerations. ISO-NE set up a battle over the proposed Killingly plant with its decision to include it in future power plans, known as Capacity Supply Obligation (CSO). Killingly is owned by NTE Energy. Without a commitment from ISO-NE to use the 650 megawatts the plant would have supplied, building the Killingly Energy Center would likely be a less economically viable project. Whether NTE would simply scuttle the project at that point is unknown. NTE did not reply Friday morning to a request for comment. But it noted that NTE would have the option to re-enter Killingly in the capacity market at a later time but would need to begin the qualification process for new resources again.